This invention relates to a process for polymerizing olefins. In another aspect, this invention relates to a novel catalyst system for the polymerization of alpha-olefins. In another aspect, this invention relates to a novel catalyst component to be used in the polymerization of alpha-olefins. In still another aspect, this invention relates to a method for preparing a novel catalyst system for the polymerization of alpha-olefins. In still another aspect, this invention relates to a method for preparing a novel catalyst component to be used for the polymerization of alpha-olefins. In another aspect, this invention relates to a process for the polymerization of alpha-olefins in the presence of a catalyst comprising a catalyst component which is obtained by treating a magnesium dihydrocarbyloxide compound-tetravalent, halogenated titanium compound reaction product with a dihydrocarbylmagnesium compound. In still another aspect, this invention relates to a catalyst system useful in the polymerization of alpha-olefins which comprises two components with the first component being obtained by mixing a magnesium dihydrocarbyloxide compound with a tetravalent, halogenated titanium compound and then contacting the resulting product with a dihydrocarbylmagnesium compound, and the second component is an organometallic compound.
It is known to polymerize alpha-olefins and mixtures thereof according to the low pressure process of Zeigler. In this process, the catalysts used are prepared from mixtures of compounds of elements of Subgroups IV to VI of the Periodic Table and the organometallic compounds of the elements of Groups I to III of the Periodic Table. The polymerization is generally carried out in suspension, in solution or even in the gaseous phase.
Furthermore, processes wherein a magnesium dihydrocarbyloxide compound is reacted with a compound of an element of Groups IV to VI of the Periodic Table are known. For example, according to U.S. Pat. No. 3,644,318 a compound of an element of Groups IV to VI from the Periodic Table, e.g., titanium tetrachloride, is reacted with a magnesium dihydrocarbyloxide compound, such as magnesium methoxide, to form a catalyst component. This catalyst component is then mixed with an organoaluminium compound as co-catalyst.
U.S. Pat. No. 3,901,863 discloses the reaction of a magnesium dihydrocarbyloxide (alkoxide), a titanium alkoxide and an aluminum halide compound to produce an active catalyst component. This catalyst component is then used with an organoaluminum co-catalyst for the polymerization of alpha-olefins.
U.S. Pat. No. 3,718,636 first reacts the magnesium alkoxide compound with an organometallic compound, e.g., trialkylaluminum is preferred, and then reacts the product with a halogenated derivative of a transition metal, e.g., titanium tetrachloride. The resulting catalyst component is then used with an organometallic compound such as triethylaluminum as co-catalyst for the polymerization of alpha-olefins.
The activity of an alpha-olefin polymerization catalyst is one important factor in the continuous search for the ultimate catalyst to be used in an alpha-olefin polymerization reaction. The present invention provides a novel catalyst which can be used in a process for polymerizing alpha-olefins and results in a high yield of polymer. The catalyst comprises two components. One catalyst component is obtained by mixing a magnesium dihydrocarbyloxide compound with a tetravalent, halogenated titanium compound and then contacting the resulting product with a dihydrocarbylmagnesium compound. This catalyst component is then mixed with a second component, namely, a metallic hydride or an organometallic compound wherein the metal is selected from an element of Groups IA, IIA and IIIA of the Periodic Table. The treatment of the product obtained by mixing the magnesium dihydrocarbyloxide compound and the tetravelent, halogenated titanium compound with a dihydrocarbylmagnesium compound results in a catalyst component with increased activity when mixed with an organometallic co-catalyst as compared to the catalyst system in U.S. Pat. No. 3,644,318, wherein the titanium-magnesium alkoxide reaction product is not treated with a dihydrocarbylmagnesium compound as in the present invention, and U.S. Pat. Nos. 3,901,863 and 3,718,636 wherein a catalyst component comprising a magnesium alkoxide and a titanium compound also incorporate an aluminum alkyl compound.
It is an object of this invention, therefore, to provide an improved process for the polymerization of alpha-olefins.
Another object of this invention is to provide a novel and improved catalyst for the polymerization of alpha-olefins.
Another object of this invention is to increase the yield of polymer in an alpha-olefin polymerization process.
Other objects, aspects and the several advantages of this invention will be apparent to those skilled in the art upon a study of this disclosure and the appended claims.